Device for carefully detaching and removing a press-molded part from a die

ABSTRACT

A device is provided for detaching a finish-molded workpiece, made of a thermoset, from a compression molding tool and for removing the workpiece from the molding press. In order to be able to carefully detach and remove compression molded parts of any desired shape from the compression molding tool, the removing gripper, which is preferably manipulated by an industrial robot, is designed according to the invention as a dimensionally stable suction bell which is adapted to the workpiece, covers the entire workpiece in a true-to-shape manner up to the workpiece edge and, with a contact-side soft-material seating, can be brought to bear in a sealing manner against the workpiece. Pockets which are sealed off from one another and each of which can be subjected individually to a vacuum are incorporated in the soft-material seating. Each of the separate vacuum connections mutually free of reaction is provided with a monitoring device which emits a signal in the event of a drop in vacuum below a threshold value. A plurality of plungers which can be set down on opposing surfaces on the lower die are attached to the edge of the suction bell. The removing gripper can be pushed off the lower die by the plungers.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention is based on a device for removing a compressionmolded part from the compression molding tool as has been disclosed, forexample, by an article by R. Brüssel and U. Weber “SMC-Teilevollautomatisch herstellen” [Fully automated production of SMC parts],published in the journal Kunststoffe, No. 79 (1989), pages1149-1154—cited briefly below by [1].

In the method described in [1], a mixture of reactive thermosettingsynthetic resin and fibers which is matched in weight to the finishedcomponent is taken as the basis for the production of SMC parts. To beprecise, the matched quantity of raw material is obtained by cutting outcut-to-size parts of a certain size and shape from a fiber-mat sheet(prepreg sheet) delivered in roll form and by placing the cut-to-sizeparts together to form a mat stack. Such a mat stack is inserted in aprecise position into an open molding tool of a press. The molding toolis heated to a temperature at which the reactive synthetic resin reactschemically and sets. By initially slow closing of the molding toollocated in the press, the raw material introduced is at first onlyheated, as a result of which the synthetic resin becomes soft andfree-flowing. The molding tool is then closed under controlled force andspeed, the softened raw material flowing away laterally and completelyfilling the cavity of the molding tool in the process. After thisfilling of the impression, the molding tool is kept closed for a timewith defined force, so that the synthetic resin can completely react andharden. It is only at this point that the molding tool can be opened andthe finished SMC part removed therefrom.

To demold the molded SMC part from the molding tool, pin-like ejectorsare integrated at least in the lower die in [1]. When the molding toolis opened, i.e. when the upper die is lifted upward, first of all theSMC part must be released from the impression of the upper die, so thatthe SMC part reliably remains behind in the lower die. This can beensured by ejector pins integrated in the upper die or—if compressionmarks must not be recognizable on the workpiece surface molded on thetop side—by a parting agent applied to the impression surface of theupper tool. Detaching the workpiece from the upper tool impression,despite a parting agent applied to the surface, certainly requires acertain expenditure of force between molded part on the one hand andupper die on the other hand. However, the opening force of the press isalways sufficient for this purpose. After the opening of the moldingtool, the ejectors provided in [1] at any rate in the lower die comeinto action and lift the SMC part slightly from the impression of thelower die, so that it only rests loosely in the lower die and can easilybe removed. A disadvantage with the plant according to [1] is that ithas to rely on the use of integrated ejector pins for detaching themolded part from the lower impression. These ejector pins requirethickened or stiffened material portions in or on the workpiece at theworkpiece-side attachment locations, and these thickened or stiffenedmaterial portions, during the reaction or cooling of the plastic, leadto shrinkage, which stands out as slight sink marks on the visible sideof the molded part. In the case of visually critical paneling parts, inparticular in the case of enameled body parts, such sink marks wouldturn out to be unsightly and cannot be accepted. In addition, there isthe risk of fritting of the one or the other ejector pin during thecompression processing of reactive preliminary masses of thermosets, asa result of which the production process may be susceptible tomalfunctions.

For the automated removal of the SMC part resting loosely in the lowerdie of the previously known press on account of the ejector pins, aremoval implement having a gripper is provided in [1], this grippermoving into the press, taking hold of the molded part there anddepositing it in an automatic molded-part magazine if it issatisfactory. According to [1], the molded part still located in thegripper is already checked for completeness by means of photoelectricbarriers during the removal; if defects are discovered, an alarm isgiven and the production system is stopped temporarily for inspectingthe molding tool. Nothing is stated in [1] with regard to the operatingprinciple of the gripper itself. In any case, the known gripper isdesigned in its function in such a way that it can only remove an SMCpart resting loosely in the lower die from the press, but is not able todetach the molded part from the impression of the lower die as well.

On account of the surface waviness, due to thickened material portionswhich have to be provided for ejector pins, on the visible side of themolded plastic parts, such ejector pins, in particular in the productionof visually critical extruded plastic parts, have to be dispensed withand the molded parts have to be detached from the lower die in anotherway. Irrespective of, this, dispensing with ejector pins is alsoadvisable in the cases in which—due to a certain workpiece form—thevisible side of the workpiece has to be assigned to the impression ofthe lower die.

The applicant is not familiar with any method of detaching SMC moldedparts from the lower die which can be automated or mechanized and whichwould not need ejector pins integrated in the tool. In tools withoutejector pins, work is carried out with a parting agent appliedbeforehand to the surface, and the finished workpiece is manuallydetached from the lower die with difficulty after the opening of thepress. In this case, a pointed object is used in an attempt to releasethe workpiece locally from the impression at an edge location point andcompressed air is injected in order to widen the area of the resultinggap. In this way—locally mechanical release of the edge and pneumaticwidening—the entire workpiece is gradually detached from the lowerimpression. Apart from the amount of time required for this and thearduous work on a heated tool and in ergonomically unfavorable spaceconditions, the workpiece is damaged often enough during this procedure,so that is becomes useless. In particular parts of large area areespecially at risk during detachment effected in this way, since thecenter of the component, which in this case lies further away from theedge of the component, may still possibly adhere firmly to the toolimpression despite a released edge. Lifting the already releasedcomponent edge too forcibly may stress the molded part, stillexperiencing the heat of reaction, beyond the elastic limit and causepermanent deformations in it.

A method of producing thermoplastic molded parts is shown in Europeanpublication EP 461 365 B1, =[2], in which method a quantity of heatedand softened thermoplastic adapted in terms of weight is inserted intoan open molding tool of a press, the plastic compound is extruded intothe cavity of the molding tool by closing the latter, and then theworkpiece still located in the molding tool is cooled and finallyremoved from it. According to [2], a suction gripper which ismanipulated by a manipulator movable in three axes and has two roundsuction cups per workpiece is used for the automated removal of thefinished workpiece from the opened compression molding tool. Normally,during the manipulation of hard parts by suction grippers, adaptablesuction cups of flexible material are used in which the suction-cup edgeis designed as a thin sealing lip which opens like an umbrella towardthe bottom and which can readily conform to surface unevenness andtherefore provide a sound seal. In [2], reference is not expressly madeto the fact that the removing gripper is merely used to remove themolded part already detached from the lower die and therefore only lyingloosely in the lower die; however, this may be assumed in view of onlythe two suction cups per workpiece. There is also the fact that there isvirtually no potential for malfunctions to occur due to fritting of theejector pins during the compression processing of thermoplastics whichdo not react chemically, and the detachment of the molded part from theimpression by means of ejector pins during the processing of such amaterial may also be assumed as a rule without expressly mentioning it.

The object of the invention is to improve the device so that compressionmolded parts of any desired shape can be carefully detached from thecompression molding tool and removed from it.

This object is achieved according to the invention.

Accordingly, the removing gripper is designed as a dimensionally stablesuction bell which is adapted to the workpiece and by means of whichvery high forces can be exerted on the workpiece by a vacuum which actson the top workpiece surface, these forces enabling the workpiece to becarefully detached from the impression of the lower die. During theaction of force, the workpiece is in no way deformed but rather isstabilized in its desired shape.

Expedient configurations of the invention are apparent from thedependent claims. In addition, the invention is explained in detailbelow with reference to an exemplary embodiment shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic overall view of a process plant in a plan view,

FIG. 2 shows a vertical sectional view of the press and the removingtool attached to the workpiece,

FIG. 3 shows an enlarged longitudinal section through an exemplaryembodiment of a safety valve for maintaining the vacuum despite anyleakage in one of the pockets, subjected to vacuum, of the removingtool,

FIG. 4 shows an enlarged illustration of the detail IV in FIG. 2,showing a sealing profile between two adjacent pockets of the removingtool,

FIGS. 5 and 6 show two further exemplary embodiments of sealing profilesbetween two adjacent pockets of the removing tool in an illustrationsimilar to FIG. 4, and

FIG. 7 shows a simplified plan view of the removing tool according toFIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The process, on which the invention is based or which precedes theinvention, for the mass production of SMC parts may be briefly explainedwith reference to the process scheme according to FIG. 1. The SMC partsare produced from a fibrous, reactive resin compound which is providedas initial product in the form of a virtually endless resin-mat sheet 4wound into a supply roll 1. To maintain the reactivity of the syntheticresin in the resin-mat sheet, the latter is covered with a protectivefilm 2, which is pulled off only just before the processing of the resinmat and is rolled up to form a separate coil 2. The protective film isdeflected against the processing direction of the resin mat toward thecoil 2 via a reversing bar located in the vicinity of thecutting-to-size table 3. The side edges of the resin-mat sheet areunsuitable for further processing and are cut off by a respectivestationary cutting tool. The lateral scrap strips cut off at the sheetedge are likewise deflected via reversing bars into scrap containers.

The usable part of the resin-mat sheet is divided on the cutting-to-sizetable 3 provided with a very hard bearing surface, various cut-to-sizepieces 5 of defined shape and size being cut out of said resin-mat sheetand being stacked to form a multi-layer resin-mat stack having a certainnumber and arrangement of layers. The scrap parts which accumulate inthe process and cannot be used further are discharged into acorresponding scrap container 9. For mechanized and automatedcutting-to-size, a cutting-to-size robot 6 is provided in the exemplaryembodiment shown in FIG. 1 and guides a high-frequencyrotary/oscillating saw blade 8 which is driven by a suitable motor 7.

The cut-to-size pieces 5 cut by the robot 6 on the table 3 are stackedon a separate weighing and stack-forming device 17 to form a resin-matstack, the cut-to-size pieces being manipulated and moved by amanipulating robot 10, which in turn is provided with a resin-matgripper 11 (not to be dealt with in any more detail here) which isspecifically designed for this task and this substrate. Once theresin-mat stack has been formed in an appropriate shape for a newworkpiece, the manipulating robot inserts said resin-mat stack in adefined position into a heated molding tool 18 of the molding press 12.The compression molding tool 18, which can be opened and closed by themolding press 12, consists of a lower die 24, mounted on the press table21, together with its impression 26 and of an upper die 23, mounted onthe press ram 22, together with impression 25. The heating of themolding tool 18 is not shown here.

By means of the press, the molding tool 18 is closed until the shapingsurface of the cavity comes into contact with the inserted resin-matstack and is clamped in the closing direction with a defined force,which is still small to begin with. Due to the contact with the hottool, the resin compound heats up and softens as a result. On account ofthe closing force of the molding tool, the resin compound begins to flowand as a result finally completely fills the cavity of the increasinglyclosing molding tool 18. The tool is then held in the closed state for acertain time with increased force, in the course of which the resincompound is thermally cured. After this curing time has expired, thepress 12 opens the tool, with the finished SMC part still lying in thelower, fixed tool half. The SMC part can be removed from the press anddeposited in a cooling station 15 by a removing robot 13 provided with aremoving tool 14. While the cutting-to-size and manipulating robots 6and 10, respectively, prepare a new resin-mat stack, the opened moldingtool 18 is cleaned by two cleaning robots 16, so that it is ready forreceiving a new resin-mat stack.

The present invention involves a device for carefully detaching thefinish-molded plastic workpiece 19 from the impression 26 of the lowerdie 24. In view of the visual requirements imposed on the visibleworkpiece surface 20 lying at the top, no ejector pins may be providedin the lower die.

Nonetheless, in order to be able to carefully detach and removecompression molded parts of any desired shape from the impression 26 ofthe lower part 24 of the compression molding tool 18, a removing gripper14 is provided which is designed as a dimensionally stable suction belladapted to the workpiece. The removing gripper is arranged on the wristjoint 39 of the multi-axis manipulating robot 13 and can be freelymanipulated by it. The underside of the bell-shaped removing gripper isshaped in such a way that it covers the entire workpiece surface 20,exposed in the lower die 24, in a true-to-shape accurate manner right upto the workpiece edge accessible in the lower die 24. On the inside, theremoving gripper, on the contact side of the suction bell, is providedwith a soft material seating 27 which can be brought to bear against theworkpiece 19 in a sealing manner at least along the entire workpieceedge by means of certain sealing strips, a gap-like intermediate spacebeing enclosed between suction bell and workpiece 19. In the exemplaryembodiment shown, this intermediate space is subdivided into a pluralityof pockets 29 by a plurality of sealing lines running crosswise over theworkpiece surface to be seized, the pockets 29 being sealed off from oneanother by the sealing profiles 28. Each of the pockets is provided witha separate vacuum connection 30 and thus can be subjected to vacuum onits own. In view of the reaction temperatures for curing thethermosetting SMC parts, the sealing profiles used for forming thesealing lines should be made of a material which istemperature-resistant at least up to about 140° C.

The sealing profiles 28 follow the course of the exposed workpiecesurface 20 in a true-to-shape manner and can be brought to bear againstthe workpiece surface in a sealing manner. The relaxed, end-face profileshape 32 of the sealing profile is arched. It is not until it is underthe effect of the vacuum and the applied pressure effected by theambient air pressure that the sealing profile 28 is pressed flat againstthe workpiece surface at the end face. It is certainly true that, by theexertion of force in the pulling direction, the residual gas trapped inthe pockets can expand, the gap between workpiece and suction bell canwiden and the sealing profile can lift somewhat from the workpiecesurface. However, due to the arch 32, which forms again in thissituation, of the sealing end face, its sealing contact with theworkpiece surface is retained. Even under the action of force andconsequent widening of the pockets 29, the sealing profiles 28 remaintight and the vacuum is retained unchanged.

A situation may arise in which either the vacuum does not reach itsdesired level at all in one of the pockets 29 or the vacuum collapses inone of the pockets during the operation for releasing the workpiece bythe removing gripper. There may be several reasons for this. One reasonmay be a defective workpiece, e.g. a workpiece having a rough or poroussurface. Another reason for an inadequate vacuum may be local damage ordisturbance of the sealing profile due to a foreign body orcontamination. A further possibility for collapse of the vacuum in apocket may be overstressing of the elasticity of the sealing profile, sothat it lifts locally from the workpiece surface 20; ambient air thenflows briefly into the pocket concerned and the vacuum collapses veryquickly.

The individual pockets 29 are connected to one another via the supplylines to the individual vacuum connections 30. A respective safety valve31 is arranged in the vacuum connection of each pocket 29 so that,despite the external line connection between the pockets and despite anyleakage in one of the pockets, the vacuum does not collapse in all theother pockets and the entire removing gripper does not becomeineffective. This safety valve 31 is designed in such a way that, in theevent of any collapse of the vacuum in one of the pockets, the vacuumconnection concerned is closed by the associated safety valve, so thatno ambient air, or at most very little ambient air, can penetrate intothe other pockets from the pocket affected by leakage.

An exemplary embodiment of such a safety valve 31 is shown in FIG. 3. Anessential part of this device is a check valve 55, which, duringundisturbed operation, stays in the open position shown, which on theone hand is brought about by the restoring spring 58 and on the otherhand is predetermined by the supporting cage 61. In this open positionof the safety valve there is an unhindered flow connection between thetwo line connections leading outward.

The valve member of the check valve 55 is guided in an axially movablemanner by a delay piston 56, which in turn can slide in a piston space57 largely closed on the outside. When the vacuum is superimposed, theair still located to begin with in the connected pocket 29 flows frombelow (connection 30) through the check valve 55 into the vacuum lineleading to the right in FIG. 3. In the process, the intensely flowingair exerts a force acting in the closing direction on the check valve55, the force definitely exceeding the force of the restoring spring 58.However, the air which is trapped in the piston space 57 and displacedby the delay piston 56 during such a closing movement, and which canonly escape into the open via the adjustable delay restrictor 59,permits only very slow closing of the check valve 55. This delay time isproportioned in such a way that the associated pocket can be reliablyevacuated. Nonetheless, the check valve 55 finally shifts into theclosed position only during prolonged evacuation times due to leakage.However, if the desired level of vacuum in the connected pocket isreached within the delay time, the evacuation flow stops and the checkvalve 55 automatically returns under the effect of the restoring springfrom a partially closed intermediate position into the open positionshown.

If the vacuum should suddenly collapse in the connected pocket duringthe operation of the removing gripper, an intense evacuation flow againoccurs in the safety valve, this evacuation flow lasting longer than thedelay time, so that the check valve 55 shifts into the closed positionwith lasting effect. This local closing is intended to prevent a lastingflow of infiltrated air into the vacuum feed lines of the other pocketsand to maintain the vacuum in the other pockets. In this state of theclosed safety valve, vacuum feed is only possible via the adjustablebypass restrictor 60 across the check valve to the connected pocket.This is intended to ensure, if need be, a vacuum supply to the connectedpocket in the event of the leakage forming again for any reason. Thismay happen, for example, by the removing gripper being pressed firmlyagainst the workpiece 19 once again by the removing robot 13.

If a pocket 29 of the removing gripper 14 should remain permanentlyleaky during a removing operation, the associated safety valve 31likewise remains permanently closed and only a small leakage flow ofinfiltrated air flows constantly into the vacuum supply via theadjustable bypass restrictor 60. However, this small infiltrated airquantity has no further harmful effect for maintaining the vacuum in theother pockets of the removing gripper. The vacuum there can nonethelessbe easily kept at a level sufficient for detaching the workpiece 19 fromthe impression 26 of the lower die 24.

Of course, a leakage from the one or the other pocket 29 of the removinggripper 14 constitutes a disturbance which should be removed. On theother hand, an individual pocket which becomes leaky cannot be readilydetected during automated operation, since the workpiece can be reliablyheld in place on the removing gripper by a still sufficient number ofother pockets. Nonetheless, in order to be able to detect any leakage atthe individual pockets, the vacuum feed to each individual pocket 29 isprovided with a monitoring device 33 in the form of a barometer withintegrated signal transducer. If the level of the respective vacuumdrops below a pre-adjustable threshold value, this monitoring deviceemits a signal. Thus not only can the fact that a leakage has occurredat one of the pockets be detected, but the pocket at which the leakagehas occurred can also be already established. As a result, on the onehand, the workpiece just removed can be specifically examined for anydefects; on the other hand, the removing gripper itself can bespecifically inspected for any foreign bodies in the sealing region orfor damage to the seals. In addition, the signals, accumulating in thecourse of mass production, from the monitoring devices 33 can beevaluated for statistical purposes. In this way, for example, it can bediscovered whether certain pockets become leaky especially frequently,and the magnitude of the vacuum loss, the phase of a working cycle inwhich the vacuum loss occurs and the speed with which the vacuum dropscan be revealed. Together with recording the causes of the leakage,specific countermeasures which improve the production process can thenbe taken. Possible causes of leakages are, for example: workpieceporous, foreign bodies on sealing profile, sealing profile contaminated,sealing profile defective.

If the removing gripper 14 manipulated by the removing robot 13 isproperly attached to the workpiece 19 located in the open tool of thepress 12 and the vacuum is superimposed on the individual pockets 29 bythe valve 40, the operation for carefully detaching the workpiece fromthe impression 26 can start, in the course of which rather high forcesmay possibly have to be exerted. In order to relieve the robot, inparticular the working arm, the joints and drives, from the developmentof excessive forces on the one hand, but in order to be able to exertreally high forces on the vacuum-held workpiece for detaching the latteron the other hand, a plurality of plungers 36 are attached to the edgeof the suction bell and lie outside the region of the lower impression26. The removing tool can be pushed off the lower die using theseplungers, which can be actuated by servomotor and can be set down onopposing surfaces 37 on the lower die 24.

In the exemplary embodiment, four brackets 38 which project outward andin which pneumatic cylinders 35 are mounted are attached to the outeredge of the removing gripper 14. A respective pneumatic cylinder isarranged close to each corner of the removing gripper, which isrectangular in plan view. The piston rods of the piston rods, which canbe moved back and forth in the lifting direction by these pneumaticcylinders in a servomotor-operated manner, constitute the plungers 36referred to. The pneumatic cylinders 35 can be supplied with compressedair via the main valve 41.

The phase of detaching the workpiece from the impression is initiatedwith the activation of the compressed air, in the course of whichcompressed air is transmitted via a distributing device 42 to theindividual pneumatic cylinders. Different “distribution programs”, e.g.two distribution programs, can be realized by means of the distributiondevice. For this purpose, the distribution device has a valve elementwhich is both rotatable and axially displaceable in a fixed housing. Oneof the distribution programs, which are preset in the design of thedistribution device, is selected by axially positioning the movablevalve element within the housing. The program itself is realized byrotation of the valve element about its longitudinal axis.

The pushing-off force can be exerted in an intermittent or pulsatingmanner by the effect of the distribution device 42, the location of theforce, which acts for a short time in each case, changing cyclically. Asa result, it is also possible to carefully remove from the impressionthose workpieces which sit very tightly in the impression. The pneumaticcylinders are advantageously provided with a displacement sensor, bymeans of which the stroke covered by the associated plunger 36 can bedetected. The pulsating pushing-off of the removing gripper 14 from thelower die 24 is continued until all four displacement sensors signal asufficiently large stroke, from which it can be inferred that theworkpiece has been detached from the impression at all four corners.

The simplest distribution program of the distribution device 42 consistsin all four connected pneumatic cylinders being supplied simultaneouslywith compressed air and accordingly in the removing gripper being pushedoff the lower die 24 at all four corners with the same force andsynchronously. If a situation should arise in which the workpiece cannotbe readily detached from the impression 26, another distribution programcan be selected. Such modified programs can provide for the individualpneumatic cylinders to be acted upon with compressed air and relievedagain cyclically one after the other. In this case, the individualpneumatic cylinders may in each case be acted upon in turn by compressedair with a phase displacement and may be completely relieved in between,so that the pushing-off force is only effective at one corner in eachcase, although the effective location of the pushing-off force ischanged cyclically. In a modification of the distribution program,interim partial relief of the pneumatic cylinders may be provided, sothat a minimum pushing-off force is constantly effective over the entiregripper circumference. Also conceivable is a further distributionprogram in which in each case two pneumatic cylinders are jointly actedupon by pressure at the same time and the other two are relieved orpartly relieved and this pairing of loaded and relieved pneumaticcylinders is cyclically transposed.

Finally, two modifications, indicated in FIGS. 5 and 6, of the removinggrippers 14′ and 14″, respectively, are to be briefly dealt with.Whereas in the removing gripper 14 shown in FIGS. 2 and 4 a full-surfacesoft-material seating 27 is provided on the inside, from which thepockets 29 are fashioned and narrow sealing profiles 28 are left betweenadjacent pockets, in the removing gripper 14′ shown in FIG. 5 thepockets 29′ are formed by individual intersecting sealing strips 45which abut against one another in a sealing fashion being screwed ontothe inside of the shell of the removing gripper. In the exemplaryembodiment of the sealing strips which is shown in FIG. 5, these sealingstrips have two sealing lips 46 at the side in contact with theworkpiece surface 20, these sealing lips 46 being arranged in mirrorimage and projecting in their relaxed shape 46′ slightly in thedirection of the workpiece 19. Nonetheless, on account of this elasticdesign of the sealing lips, the sealing strip 45 can always conform tothe workpiece surface 20 in a sealing manner even in the case of largerrelative displacements and local geometrical errors.

In the exemplary embodiment, shown cut away in FIG. 6, of a removinggripper 14″, pockets 29″ are incorporated in its supporting shell, whichis made of a hard and loadable construction material, and narrow websrunning crosswise are left in said shell. Grooves 50 of, for example,rectangular cross section are milled in these webs, and acorrespondingly shaped seal 51 made of a soft material is adhesivelybonded in place in said grooves 50 in a firmly adhering manner. Here,too, in order to ensure a certain elasticity of movement andconformability, the exposed contact side is of arched design in itsrelaxed shape 53.

1-9. (canceled)
 10. A device for detaching a finish-molded plasticworkpiece from a lower impression of a compression molding tool, whichis split into a lower die with a lower impression and an upper die withan upper impression and which can be opened and closed by a moldingpress, and for removing the workpiece from the molding press, duringproduction of molded parts of reactive raw compounds of a thermoset,comprising a removing gripper which can be manipulated in a plurality ofaxes, wherein the removing gripper, which is also intended for detachingthe workpiece from the lower impression of the lower die, is designed asa dimensionally stable suction bell adapted to the workpiece, covers theworkpiece entirely in a true-to-shape manner on a workpiece surface,exposed in the lower die, up to the workpiece edge accessible in thelower die and, with a soft-material seating on the contact side of thesuction bell, can be brought to bear in a sealing manner against theworkpiece at least along the entire workpiece edge, and wherein it ispossible for vacuum to be applied to a gap-like intermediate spaceenclosed between the suction bell and the workpiece.
 11. The device asclaimed in claim 10, wherein the soft-material seating covers theworkpiece entirely at least along certain sealing lines and follows acourse of the workpiece surface, exposed in the lower die, in atrue-to-shape manner, it being possible for the sealing lines to bebrought to bear against the workpiece surface in a sealing manner, andwherein pockets which are sealed off from one another and to whichvacuum can be applied are exposed between the sealing lines.
 12. Thedevice as claimed in claim 11, wherein each of the pockets which aresealed off from one another is provided on the inside on the suctionbell and is provided with a respective separate vacuum connection. 13.The device as claimed in claim 12, wherein a respective safety valve isarranged in each respective separate vacuum connection, which safetyvalve, upon any collapse of the vacuum in one of the pockets, closes thevacuum connection concerned in such a way that no more than only verylittle ambient air can penetrate into the other pockets from the pocketaffected by leakage.
 14. The device as claimed in claim 12, wherein avacuum feed to each individual pocket is provided with a monitoringdevice which emits a signal if the level of the respective vacuum dropsbelow a pre-adjustable threshold value.
 15. The device as claimed inclaim 10, wherein a plurality of plungers which lie outside the regionof the lower impression, which can be set down on opposing surfaces onthe lower die, and which can be moved back and forth in the liftingdirection in a servomotor-operated manner, are attached to the edge ofthe removing gripper, and wherein the removing gripper can be pushed offthe lower die by the plungers.
 16. The device as claimed in claim 15,wherein the plungers are provided with a displacement sensor by which astroke covered by the plunger can be detected.
 17. The device as claimedin claim 10, wherein the removing gripper is attached to a wrist jointof a six-axis industrial robot.
 18. The device as claimed in claim 11,wherein sealing profiles used for forming the sealing lines are made ofa material which is temperature-resistant at least up to about 140° C.